Nomenclature
CAS number: 10035-10-6
HBr; mol wt 80.91.
H 1.25%, Br 98.76%.
Description and references
A soln of hydrogen bromide gas in water. Marketed
in various concns, e.g., 50% HBr, d 1.517; 40% HBr, d 1.38; 34%, d
1.31; 10%, d 1.08. Lab prepn according to the eq H2SO4 + KBr → KHSO4 + HBr: Heisig, Amdur, Inorg. Synth. 1, 155 (1939). See also Hydrogen Bromide.
Properties
Colorless or faintly yellow; slowly darkens on
exposure to air and light. Miscible with water, alcohol. Corrosive. Keep protected from light. When
dil hydrobromic acid is distilled, a weaker acid comes over first
and when a very concd acid is boiled, HBr gas chiefly distills over
first; in both cases a “constant boiling” acid contg about 47.5% HBr
remains which distills unchanged at 126°. The bp and compn of the
azeotrope varies with pressure: at 100 mm, bp 74.12°, compn 49.80% HBr; at 400 mm, bp 107.00°, compn 48.47%; at 700 mm, bp 122°,
compn 47.74%; at 800 mm, bp 125.79°, compn 47.56%: Bonner et al., J. Am. Chem. Soc. 55, 1406 (1933).
Aq solns are strongly acid. The satd aq soln contains 68.85% HBr
at 0° and 66% at 25°.Caution
Strong irritant.Use
The concd acid is used principally in analytical
chemistry and organic prepns. Catalyst.
Therapeutic Category
Sedative.
Therapeutic Category (Veterinary)
Has been used as a sedative.
Keywords
Sedative/Hypnotic